There is 7/8" difference in the tires I am not sure that would distribute the extra 300 pounds (375 versus 675) any better - besides, some of my better customers have come from guys using bigger and heavier mowers - as I said for the most part, I am on soft ground and of course there is the extra $2,500 to $3,000 which has to be taken into account, then I would half to buy a trailer and always carry one of my 21" with me to get in the tight places.